Fuel atomizing nozzle



OGL 14, 1952 T. M. BALL 2,613,997

FUEL ATOMIZING NozzLE:

Filed Nov. 5, 1948 Patented ct. i4, i952 FUEL ATOMIZING NOZZLE lThomasM. Ball, Detroit, Mich., assigner to Chrysler Corporation, HighlandPark, Mich., a

corporation of Delaware Application November 5, 1948, Serial No. 58,401

i Claims.

The present invention relates to atomizing 'nozzles such as used forsupplying fuel to combustion chambers and more particularly to thesocalled return flow or continuous bypass type nozzle.

A broad object of this invention is to produce an atomizing nozzleoffering the cool operating behavior and other marked advantagesinherent in return flow nozzles and yet being unhampered by the usualdisadvantages attendant with the problem of confining the fuel,air-free, to its assigned passages.

Another object is to provide a nozzle of which the swirl chamber has aportion of its confined fuel withdrawn therefrom for bypassspurposeswithout any prospects of air being sucked into the bypass passages alongwith the fuel.

A further object is to provide a spray-type structure of simpleconstruction and relative ease of manufacture.

Yet another object is to produce a nozzle built on return fiowprinciples providing positive and adjustable seals for the holderwhereby various.

stages are effectively isolated from one .another and from the outsideto insure against all possible leakage. Still another object is toprovide at the relatively cooler operating portions of a nozzle, thatis, where the danger from excessive heat deterioration is precluded, adeformable seal susceptive of exact and controlled adjustment such thatcommonly experienced leakage may be avoided.

Yet a further object isto provide in a nozzle effective heat dams by thefuel passages themselves for protection of the less rugged metallicportions. A Still a further object is to produce an improved spraynozzle comprising a few parts and being simple in operation, easy toassembly and disassemble, and capable of being manufactured at low cost,Additional objects and advantages are within the scope of this inventionsuch as relates to the arrangement, operation and functioning of therelated elements of the structure to various details in combination ofparts, elements per se and to economies of manufacture and numerousother features as will be apparent from a consideration of thespecification and drawings of a form of the invention which may bepreferred .in which: l Fig. 1 is a longitudinal section of a fuel nozzleembodying the invention; f-

Fig. 2 is a perspective view of a kerfed. member for the spray tip inwhich the general angularity of the face passages has been renderedoblique; and

Fig. 3 shows a form of the invention employing a modified spray tip.

In particular regard to Fig. l of the drawing, the nozzle showncomprisesin essentials an inner casing surrounded by, and in radial spacing, toan outer casing or sleeve. This outer casing terminates in a tip whichmay be received by the holder le. An inlet passage I2 and an outletpassage Id may be formed in the holder to establish fuel supply andbypass return conduits. The outlet passage i4 communicates with a returnchamber I6 forming an open end for the holder and being restricted atits inside end by the face i8 `of an internal annular flange 22. Flange22 may be disposed inwardly to define an aperture 24 which enters into aradially extended annular recess 26. In axial continuation of recess 26there may be provided in the holder a threaded portion 28 for adjustablereception of the `head 30. By means of thisthreading the head maybe'adjustably positioned against washer 32 which is interposed toprovide a liquid-tight seal between the two members I0 and 30. Thiswasher may be constructed of some material suitable to withstandrelatively high temperatures and may be desirably formed from annealedcopper. The head 30 may be hollow and consist axialwise of a threadedportion 33 which flares into an annular chamber 34. The walls ofthe'annular recess 34 merge inwardly to produce at their end an innersurface 36. The recess 34 thereby assumes more or less the form of atoroidal chamber. Supported within the head may beprovided a tip proper4E! comprising two elements'42 and I4v arranged coaxially. The outerelement 42 may be formed with an ejection orifice 46 and may beinterfaced as at 48 vwith the complementary'e'lement 44. Member 44 onthe other hand maybe provided with a companion rim flange 5I withinwhich may be received element 42 in axial aligne` ment, and'providedalso with slots ory kerfs 5.". cut into its interface 58.` The twocooperating pieces form in effect a member defining ac'entral swirlchamber 54 into which the passages 52 feed tangentially. For forciblyabutting -and supporting the swirl chamber member" andv constituting anessential part of the 'inner casing, there may be provided a sleevelv''18 having a terminal member orhead-SZformed with passages as at E4..-The endiof-this Spassaged terminal may be faced off as'at itoprduce afloor for the swirl chamber" and maybe provided at its extreme peripherywith an annular recess 68 which serves to space the faced off memberfrom the rear of the spray tip proper. There thus results an annularchamber located radially on the fringes of the actual swirl chamber. Thetake-off passages 64 located around the annular recess 68 convergetoward the rear of the nozzle and merge into a central conduit 12 whichserves as bypass for the head. .An annular radial ange 14 has a threadedcircumference by means of which the sleeve is positioned within the headdescribed and by means of which fluid seals are maintained between thetip proper and the associated structure. Through the flange 14 there maybe provided bores such as at 16 to provide for passage of fuel. Theinner casing extends inwardly of the nozzle and may include a neckeddown portion 82 which serves as a toroidal shank. Shank 82 may bereceived in the aperture 24 of the holder and may extend on into thereturn chamber I6 thereof. This shank may thus serve to dene an annularrecess adapted to receive a deformable grommet or ring 84 forming a sealbetween the inner and outer casings. This packing is preferably of asoft metal such as silver for example, but on the other hand may be of aplastic or rubber-like consistency. The primary concern in choice of itscomposition is no doubt that the seal withstands the temperature in thenormal operating range of the nozzle and the less elevated temperatureswill permit use of less heat resistant materials. Bore I6 may beobserved from the figure to be tapped to form an adjustable gland recessmeans. Provided for reception in this recess means may be a gland orclamping means 86 in which is formed a hollow bore 92. By appropriateemployment of the vclamping means the seal 84 may be adjusted so as toprovide a non-leaking packing as between the casings and to this end themember 86 may be formed with means for receiving an adjusting tool as byslot 94 for varying the pressure on the seal. The tapped bore I6continues through to the end of the holder and is adapted to be blankedoff by a plug as at 96. This plug may have a lip 98 arranged to engage awasher such as shown at |02 to provide a seal as between the plug andthe holder. This washer may be made of annealed copper or the like. Theplug 96 may be formed with a, recess as at |04 for embracing an Allenwrench or other adjusting means to control the compression on washer I02.

As to operation of the structure just described, conduit |2 supplieshigh pressure fuel which is fed into the high pressure stage of thenozzle.

Upon entering, the fuel will tend to fill up the annular chamber 26 andserve to provide a heat dam as between the direct line of heattransmitted through the tip of the nozzle as would ordinarily affect thenon-metallic packing 84. The transit of the iiuid is such that it passesbetween the inner and outer casings through ports 'I6 provided in theange 14 and into the toroidal chamber in part defined by recess 34.Passages 52 in the swirl member represented in the figure as beingcoplanar tend to swirl in the fuel from the tcroidal chamber into theswirl chamber 54 in a state of turbulent ow. From the swirl chamber 54the fuel ow takes two paths, as hereinafter described, into which it issplit up in varying proportions depending upon the particular nozzleoutput required. That is to say, the nozzle l is continuously bypassedand the amount of bypass bears an inverse proportional relationship tothe amount of fuel n LA sprayed out of the nozzle. The resultingproportions of the foregoing relationship depend in turn on therespective back pressure and supply pressure being maintained on thenozzle, it being the general case, for example, that if the supplypressure is increased independently of change in the back pressure orthat if the back pressure is decreased independently of change of thesupply pressure, then the bypass rate of flow from the nozzle increases.It is found, however, that the nozzle tends to admit air through theejection orifice 46 under the circumstance of certain conditions in thenozzle operating range Which sometimes prevail, for instance, when theproportion of bypassed fuel is relatively great in comparison to thefuel actually being ejected by the nozzle, and particularly so when theambient atmosphere around the nozzle (that is, the atmosphere of theflame chamber in which the nozzle is located) is under a pressure whichapproaches or exceeds certain local pressures existing internally of thenozzle. The latter said local pressures depend in part on the backpressure of the nozzle. It is, of course, undesirable that air enter orbe sucked into the nozzle and introduced into the bypass of the systemfor the reason that the air must later be purged as another operationfrom the system and cannot be allowed to remain and recirculate therein.

In the swirl chamber 54, a continuous portion of the fuel thusintroduced is swirled outwardly through the ejection orifice 46 toproduce a flame in the burning chamber. Owing to the centrifugeprinciples involved the fuel, being relatively denser than any vapors orgases which might exist in the swirl chamber due to cavitation or directentry of the air through orifice 46, will tend to hug the outside of theswirl chamber. The portions of the swirl chamber otherwise than occupiedby the fuel will be localized more or less in the center portion.Accordingly the whirling fluid will be entirely rid of any entrained airor vapors by the time it reaches the outer fringes of peripheral takeoff68. The takeoff passages 64 then can transmit only the pure fuel intothe bypass line, thereby precluding the above mentioned possibility ofsucking air in such a bypass arrangement. The bypassed portion of theiiuid will then be passed down through conduit 'I2 and into the lowpressure stage area. From the return chamber I6 this fuel will beconducted on away from the nozzle by conduit I4. With the grommet 84adjustably positioned in the strategic position between the highpressure stage and the low pressure stage, fuel passing from one stageto the other needs must pass through the swirl chamber and through thepassage l2 since between the two stages any possibility of leakage iseifectually circumvented. As regards leakage to the outside, the washers32 and |02 are so positioned as to be adjustably sealable and arethereby not subject to leakage.

Preliminary to the discussion of Fig. 2 the fact should be pointed outthat the tangential passages feeding the swirl chamber have for theirprime object the function of spinning in the fuel and producingagitation vortices in the swirl chamber. It may be found, however, thatthe turbulence desirable may be more suitably produced if the flowpassages are not strictly coplanar as represented in Figure 1 but rathercut, as in Figure 2, with the bottoms |53 of the kerfs |52 disposedalong more of a conical region such that the mean longitudinal axis ofeach passage is non-coplanar as respects the balance.

In respect to Fig. 3, the embodiment shown may have a head 230 in whichis carried the tip 240 comprising a unitary member. In one end of thetip 240 may be an axial ejection orifice 246 communicating with swirlchamber 254. Drilled through the walls of this swirl chamber may beprovided small passages 252 adapted to swirl any fluid from the toroidalchamber 234. These passages 252 are represented as being coplanaralthough it may be found advantageous to dispose these passages so as tolie oblique to the axis of the nozzle. The next succeeding member, whichcarries the tip, may have a faced off floor portion 266, at the ends ofwhich are recess means 26B. The takeoi recess may be served by passages264 similar to passages 66 above described and merging into a centralbypass conduit 212. The assemblage and operation features of thisembodiment are essentially the same as outlined in the foregoingdiscussion. The structure as disclosed may be found to be particularlysuitable for high temperature operation such as is encountered ingasturbine installations. The non-leaking system of closed circulationaifords the expedient of keeping the nozzle relatively cool and makesavailable the advantageous spray control afforded by the simpleregulation of bacl; pressure on the return line. Contemplated Within itsbroader aspects, there may be ready application of the invention to oilburning furnaces and the like.

What is claimed is:

1. An atomizing nozzle comprising a hollowi headed outer casing having acentrally restricted body and an inner casing within the body of saidouter casing received in said restriction, said outer casing havinginternal threads in the said hollow head thereof, said inner casinghaving a threaded flange received in said hollow head, and engaged bythe internal threads of the same and held thereby in spaced relationshipto the end of said hollow head, a spray tip held between and engaged bythe inner casing and said end of the hollow head, said spray tip havingan ejection orice formed therein at a location remote to said innercasing, an axially aligned cylindrical chamber behind said orifice andbeing constructed and arranged as to admit air through the ejectionorice at one end thereof during a circumstance of operation in theoperating range of the nozzle, said chamber being open-ended at theother end and said inner casing presenting a recessed transverse surfaceof a larger diameter than that of the cylindrical chamber andlongitudinally spaced from said open-ended other end and forming a floorfor the chamber extending circumferentially laterally of the open end ofsaid chamber so as to form therewith a continuous cylindrical path ofrevolution; said spray tip further having whirl-producing passagesformed therein so as tangentially to intersect said cylindrical chamberfor whirling fuel thereinto and arranged in spaced relationship to thecylindrical path of revolution aforesaid to which at least a portion ofthe whirling fuel progresses, and means for selective takeoff anddrainage from the said path of revolution, of fuel to the exclusion ofair and comprising collecting passages in said floor at the peripherythereof and intersecting said path of revolution and extendingconvergingly and axially therefrom into said inner casing.

2. An atomizing nozzle comprising a hollowheaded outer causing having acentrally restrict'- ed body and an inner casing within the body .ofsaid outer casing received in said restriction, said outer' casinghaving internal threads in the said hollow head thereof, said innercasing having a threaded flange received in said hollow head, andengaged by the internal threads of the same and held thereby in spacedrelationship to the end of said hollow head, two axially alignedelements forming a spray tip held between and engaged by the innercasing and said end of the hollow head, said spray tip having anejection orice formed therein at a location remote to said'inner casing,an axially aligned cylindrical chamber behind said orifice and beingconstructed and arranged as to admit air through the ejection orifice atone end thereof during a circumstance of operation in the operatingrange of the nozzle, said chamber being open-,ended at theY other endand said inner casing presenting a recessed transverse surface of valarger diameter than that `of the cylindrical chamber and longitudinallyspaced from said open-ended other end and forming a floor for 4thechamber extending circumferentially laterally of the open end of saidchamber `so as to form therewith a continuous cylindrical path ofrevolution; said spray tip further having whirl-producing passagesformed therein between said two said elements thereof so as tangentiallyto intersect said cylindrical chamber for whirling fuel thereinto andarranged in spaced relationship to the cylindrical path of revolutionaforesaid to which at least a .portion of the whirling fuel progresses,the longitudinal axes of said passages `being coplanar, and means forselective takeoff and drainage from the said path of revolution, of fuelto the exclusion of air and comprising collecting passages in said oorat the periphery thereof and intersecting said path of revolution andextending convergingly and axially therefrom into said inner casing.

3. An atomizing nozzle comprising a hollowheaded outer casing having acentrally restricted body and an inner casing within the body of saidouter casing received in said restriction, said outer casing havinginternal threads in the said hollow head thereof, said inner'casinghaving a threaded flange received in said hollow head and engaged by theinternal threads of the same and held thereby in spaced relationship tothe end of said hollow head, a spray tip of one-piece construction heldbetween and engaged by the inner casing and said end of the hollow head,said spray tip having an ejection orifice formed therein at a locationremote to said inner casing, an axially aligned cylindrical chamberbehind said orice and being constructed and arranged vas to admit airthrough the ejection orifice at one end thereof during a circumstance ofoperation in the operating range of the nozzle, said chamber beingopen-ended at the other end and said inner casing presenting a recessedtransverse surface of a larger diameter than that of the cylindricalchamber and longitudinally spaced from said open-ended other end of saidchamber forming a oor therefor extending circumferentially laterally ofthe open end of said chamber so as to form therewith a continuouscylindrical path of revolution; said spray tip further havingwhirl-producing passages formed therein so as tangentially to intersectsaid cylindrical chamber for whirling fuel thereinto and arranged inspaced relationship to the cylindrical path of revolution aforesaid towhich at least a portion of the whirling fuel progresses, thelongitudinal axes of said passages being coplanar, and means forselective takeoff and drainage from the said path of revolution, of fuelto the exclusion of air and comprising collecting passages in said oorat the periphery thereof and intersecting said path of revolution andextending convergingly and axially therefrom into said inner caslng.

4. An atomizing nozzle comprising a hollowheaded outer casing having acentrally restricted body and an inner casing within the body of saidouter casing received in said yrestriction, said outer casing havinginternal threads in the said hollow head thereof, said inner casinghaving a threaded flange received in said hollow head and engaged by theinternal threads of the same and held thereby in spaced relationship tothe end of said hollow head, two axially aligned elements forming aspray tip held between and engaged by the inner casing and said end ofthe hollow head, said spray tip having an ejection orice formed thereinat a 1ocation remote to said inner casing, an axially alignedcylindrical chamber behind said orifice and being constructed andarranged as to admit air through the ejection orifice at one end thereofduring a circumstance of operation in the operating range of the nozzle,said chamber belng open-ended at the other end and said inner casingpresenting a recessed transverse surface of a larger diameter` than thatof the cylindrical chamber and longitudinally spaced from saidopen-ended other end of said chamber forming a floor therefor extendingcircumferentially laterally of the open end of said chamber so as toform therewith a continuous cylindrical path of revolution; said spraytip further having whirlproducing passages formed therein between twosaid elements thereof so as tangentially to intersect said cylindricalchamber for whirling fuel thereinto and arranged in spaced relationshipto the cylindrical path of revolution aforesaid to which at least aportion of the whirling fuel progresses, the longitudinal axes of saidpassages being non-coplanar according to a generally conicalconfiguration, and means for selective takeoff and drainage from thesaid path of revolution, of fuel to the exclusion of air and comprisingcollecting passages in said floor at the periphery thereof andintersecting said path of revolution and extending convergingly andaxially therefrom into said inner casing.

THOMAS M. BALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,037,645 Vroom et al Apr. 14,1936 2,120,388 Bargeboer June 14, 1938 2,177,781 Haynes et al Oct. 31,1939 2,239,068 Wood Apr. 22, 1941 2,373,707 Peabody Apr. 17, 19452,439,257 Lum Apr. 6, 1948

